Is Radioadaptive Response A Very One-sided Something Beneficial? The Good And The Bad In The Fetal Mouse Model.

In a pile of documented investigations, the phenomenon of radioadaptive response (AR) is predominately classified into the category with beneficial effect. This is probably due mainly to that in many cell lines AR reduced gene mutations, chromosome aberrations, transformation, and cell death. However, little is known if the survivors are really normal, namely, being the same as their non-irradiated counterparts. In fact, the margin of limited applicable endpoints and the simplicity of cell lines makes it hardly possible to comprehensively justice AR using in vitro systems. In a series of studies on AR in fetal mice, different consequences were observed depending on the endpoints. Possibly as the good, which demonstrate the existence of AR in this model, the numbers of fetal mice rescued from prenatal death and malformations were significantly increased. Consequently as the bad, the survivors had a markedly high postnatal mortality, suffered severely from neurophysiological alteration and developmental retardation. The young adults were highly radiosensitive, not applicable to Yonezawa Effect. In the present study, life span shortening and life long low body weight will be reported. Taken together, these whole body studies indicate that AR is a simple phenomenon but with complicated late consequences. Concerns on such as ethics, well-being and quality of life must be taken into account before talking about possible AR application in humans in the future. This work was supported in part by the Budget for New Nuclear Crossover Research from MEXT, Japan.